This invention relates generally to a binocular viewing device and in particular to a binocular otoscope for stereoscopic observations of the ear canal.
It has been determined in the prior art that binocular type applications are desirable for producing a stereoscopic inspection for endoscopic uses, that is, for viewing the eye, the ear canal, or other targets for diagnostic purposes.
To that end, binocular ophthalmoscopes, otoscopes, and the like are known in which a pair of ocular eyepiece assemblies are retained and are slidingly movable within a housing to allow changes to the interpupillary distance, as needed, for the user. The eyepiece assemblies are defined by a body member, along with a prismatic member or mirror which reflects light to and from a centrally disposed set of fixed mirrors.
The mirrors must be aligned in a specific orientation relative to each other during the assembly phase of the instrument in order to insure a single stereoscopic image is produced when a user views a target through the twin eyepiece assemblies.
Furthermore, there may be occasions in which a user might elect to utilize the apparatus for other purposes and may require other forms of eyepieces. In an otoscope, the eyepiece optics are typically conventionally plano lens. A user may elect to use filtered or other optics to perform a specific function. Alternately, a user might elect to use a different type of mirror. Prior art scopes do not provide a convenient way of assembling the eyepiece assemblies to the housing. U.S. Pat. No. 2,757,574 describes an eyepiece assembly in which the eyepieces themselves are separately screw threaded to the remainder of the assembly. Additionally, the eyepiece assembly must be allowed to slide to preserve the ability to change the interpupillary distance.